GB600955A - Improvements in or relating to electric pulse communication systems - Google Patents

Abstract

600,955. Multiplex pulse signalling. STANDARD TELEPHONES & CABLES, Ltd. Aug. 18, 1945, No. 21148. Convention date, Aug. 19, 1944. [Class 40 (v)] In a multiplex pulse communication system, means are provided in at least one of the channels to modify the relative pulse time positions of the modulated pulse train and corresponding means at the receiver restore the original time positions. The received interleaved pulse train may comprise substantially equally spaced pulses. In one embodiment of the type described in Specification 592,585, employing four channels, the pulse generators and modulators 2, 6, 7, 8, Fig. 1, of the type described in Specifications 600,244 or 600,254, are fed from a base wave source 1, with the necessary phase-shifts in circuits 3, 4, 5, and from the signal sources 9, 10, 11, 12. The modulator outputs are mixed 'and fed to a radio transmitter 13. Interposed between the modulator 8 for the fourth channel and transmitter 13 is a pulse position translator 14 of the type described in Specification 600,256. The pulse outputs for channels one, two and three are constituted by pairs 1a, 1b, 1c, 1d, 2a, 2b, &c., Fig. 4c, whilst the output from the fourth channel modulator 8 consists of paired pulses 4a, 4b, &c., Fig. 4d. The pulse position translator 14 is adjusted to shift the first of each pair, for example, 4a to a position such as 4a1 such that the new pair 4a1, 4b fit into the gap 42, Fig. 4c, in the combined transmitted pulse train. The phase-shifter 5 is first adjusted to bring pulse 4b into the desired position in the gap. Other multi-channel systems are described in which every transmitted channel includes a pulse position translator, Fig. 5 (not shown), every received channel includes a pulse position translator, Fig. 7 (not shown), and every receiver channel gating pulse circuit includes a pulse position translator, Fig. 9 (not shown). By this means the individual trains of channel pulses in the transmission medium may comprise evenly spaced or paired-off pulses and suitable adjustments can be made at the receiver properly to gate the incoming channels and convert them, if desired, for utilization by demodulators of the shock-excited tuned circuit type operating with paired-off pulses.